Liquid dispensing device and composition therefor



Dec. 27, 1955 s. E. EATON LIQUID DISPENSING DEVICE AND COMPOSITIONTHEREFOR Filed April 19, 1951 IN VEN TOR. 514M051. fan/n20 4 TOA/ Unitfitates Paton LIQUID DISPENSING DEVICE AND COMPOSITION THEREFOR SamuelEdward Eaton, Hingham, Mass, assignor to Arthur D. Little, Inc.,Cambridge, Mass., a corporation of Massachusetts Application April 19,1951, Serial No. 221,759

12 Claims. (Cl. 222-394) This invention relates to the art. ofdispensing liquids from containers by internally-generated gas pressure,for example to self-propelled sprays and the like, and to apparatus andprocedure for eflecting such dispensing. In particular, this inventionhas to do with the provision of a container in which are the liquidto besprayed and a propellant therefor, said container being gas-tight andbeing provided with discharge-controlling orifice means,

.such as a valved nozzle, whereby the, liquid may be sprayed out as andwhen desired.

The liquid composition or product to be dispensed may be any of thosewhich commonly are, or which conveniently can be, dispensed by atomizingor spraying means, such as insecticides, mothproofers and the like;paints, varnishes, and other coating materials; perfumes, deodorants,nasal sprays and other cosmetics and various other liquid pharmaceuticaland other drug products; various liquid food-product coating materials,such as. syrups; and icings; fire extinguishing compositions; and,generally, liquid materialswhich are to be applied so as to adhere toand/or soak into surfaces and hence are ejected mainly as coarse spraysor jets rather than with fine atomization or vaporization of the sprayor jet.

Self-propelled liquid sprays are now commonly made using solutions oremulsions of the propellant liquid and the liquid to be sprayed. Thesolution or emulsion is sprayed out in the form of a fine particle sizedaerosol or mist, rather than the relatively coarse spray featuringdroplets possible with the present invention. The spray of the prior artcontains not only the desired liquid to be sprayed but also thepropellant liquid. Although the latter generally vaporizes at once uponejection and helps produce this fine spray, it is sometimes of aninflammable nature and hence a fire or explosion hazard, especially inconfined spaces. Furthermore, the amount of propellant liquid isnecessarily fairly large, being seldom less than and in some casesconstituting the entire liquid phase (the material to be sprayed thenbeing a solid dispersed or dissolved in the propellant liquid). Thepressure within the container becomes quite high, since higher pressureis required to provide and propel the usual fine sprays now employed.Propellant liquids having very low boiling points are employed to attainthese higher pressures, with the fineness of the spray being at leastpartly due to the volatilization of the propellant-liquid which ispresent in'the spray. The containers therefore must have considerablestructural strengtha requirement which demands materials now incritically short supply, such as plastics and metal, commonly metal.Steel containers, when the material to be sprayed is aqueous and/ orcontains an electrolyte, are also subject to corrosion.

Objects of the present invention include in particular the provision ofliquid dispensing containers featured by internal propellant gaspressures, such as self-propellant sprays, using considerably less thanthe usual amounts of propellant, and lower, yet still effective,pressures within the container so that if desired, lighter-weight cansor ZflZhAdS Patented Dec. 27, 1955 glass containers may be safely used.Furthermore, the propellants of this invention are, as a practicalmatter, immiscible with, and are not emulsified with the liquid tobe'sprayed, and are now non-inflammable and relatively non-corrosive,and of a greater specific gravity when in liquid phase than thatof theliquid to be sprayed. Hencefire and explosion hazards may be minimized,and, if metal containers are used, corrosion due to the propellantisgreatly reduced. In fact, the preferred propellant of this invention.frequently appears, in itself, to inhibit corrosive action of thecomposition to be dispensed when used in metal containers. This isespecially true with respect to the bottoms of such containers, due atleast partly to blanketing thereof by pools of the propellants in liquidphase;

The containers filled in accordance with this invention therefore areprovided with a three-phase system, two liquid and one gaseous. Theliquid phases are the propellant, at the bottom of the container, andthe liquid composition or product to be dispensed or sprayed, whichfloats above the propellant liquid. The gaseous phase is the vaporizedpropellant together usually with a minor amount of the other volatilizedcomponents of the systern. The liquid composition or product to bedispensed or sprayed may be a single liquid substance, or a mixture ofliquids, or a solution or suspension of solid matter in one or moreliquids.

This invention will be more fully understood by reference to theaccompanying drawing, which shows a typical container in verticalsection. The drawing shows a container 1 havingwalls ofsuitable strengthfor the intended purpose, and provided with a discharge tube or conduit2 forming a passage having an intake opening near the bottom of thecontainer but somewhat above the top level of the propellant liquid 3.Tube 2 terminates at the top in a nozzle 4, the fiuid flow to which iscontrolled by valve 5. Nozzle 4 is any suitable low pressure atomizingnozzle or simply an orifice capable of forming a jet; it requires noauxiliary air or gas flow through it to atomize or distribute or ejectthe escaping liquid. Pressure of ones finger or thumb on valve 5 opensthe valve so that the liquid to be sprayed escapes through and isatomized by nozzle 4. When this pressure on valve 5 is removed, thevalve is automatically closed by a spring 9, or by the pressure withinthe container, or both. The discharge controlling orifice means need notbe a valved nozzle since where discharge of the entire contents of thecontainer at one time is to be had, the discharge orifice at the outerend of the passage may be closed by a breakable seal to serve as thesole discharge control. The body of liquid composition or product to besprayed is indicated by the'numeral 6. As the propellant 3 vaporizes,bubbles 7 of the resulting vapor rise through the body of the liquidcomposition or product 6 to form gaseous phase 8 which is underpressure. As the liquid composition is sprayed out through nozzle 4,more of propellant 3 vaporizes to fill the additional space above thebody of liquid 6. The amount vaporized in any case is suflicient tocreate gaseous pressure enough to expel the liquid composition 6 fromthe container through tube 2 and nozzle 4.

The preferred propellant for the purposes of this invention is afluorinated hydrocarbon, usually also ch10- rinated, of the typescommonly sold under the trade names Freon or Genetron. The compounds ofthese types which are used herein (aside from any diluents which theymay contain) all have the general formula CnHnzClyFa, wherein. n is aWhole number (usually 1 or 2), x is zero or a whole number, y is zero ora whole number, and z. is a whole number, and the sum of x, y, and. zis. equal to 2n+2. Typical of such compounds which are suitable are thefollowing, with their boiling points in degrees centigrade:

Mixtures of-these compounds may be used. All of the propellant compoundsused in this invention have a specific gravity greater than that of theliquid composit on or product to be dispensed. If the liquid compositionor product to be dispensed has a specific gravity greater than that ofwater, the propellant liquid selected should have a still greaterspecific gravity. The boiling point of the propellant, at atmosphericpressure, must be below ordinary room temperature (about 20 0.), inorder to insure effective vaporization under all ordinary condtions ofoperation.

When used in glass containers, the amount and nature of the propellantof this invention should be such as to provide, when entirely in thegaseous state, a volume from about 1.2 to about times that of thecontainer, calculated at normal temperature and pressure (0 C. and oneatmosphere absolute pressure), and a vapor pressure of the propellant atroom temperature (20 C.) of between 1 p. s. i. g. and 100 p. s. i. g.Lesser amounts and pressures are generally ineffective to propel thematerial to be dispensed or sprayed properly and completely out of thecontainer, while larger amounts and pressures are apt to cause glassfragments to fly forcibly in the event of accidental breakage of thebottle, due to a thoughtless users failure to take ordinary precautionsin handling, such as careless dropping and rough tossing into metaltrash cans and the like of gas-charged containers after discharge ofliquid contents, particularly if, through carelessness, the container isat an elevated temperature. The particular range to be selected withinthe above limits will depend among other things upon the size of theglass container and upon the conditions of use. Small bottles, such aswould be used for perfumes, can safely withstand the higher pressureswithin the above range better than larger bottles such as would be usedfor insecticides, for example. Bottles which would be kept at lowtemperatures, e. g. bottles of syrups or icings which would be kept in arefrigerator and used cold, could also safely contain propellantscapable of producing such higher pressures better than could similarbottles, e. g. of insecticide sprays or aerosols intended for use intropical climates.

If the containers are formed of materials somewhat stronger than glass,such as metal, but perhaps of appreciably thinner gauge and lessstrength than that previously used and thus being more prone to ruptureat higher pressures, the above figures for volume and vapor pressure maybe somewhat higher with the maximum pressure to be generated beingdictated by the strength of the container.

The vapor pressure of the propellant at room tempera- 1 ture, when glasscontainers are used, may for example be around 5 p. s. i. g., or lower.The pressure employed depends also upon the type of delivery desired.For atomization, the pressure cannot be appreciably lower than around 2p. s. i. g., assuming suitable nozzle design,

whereas for forming a simple jet, without appreciable the propellantwhich dissolves in the liquid composition or product to be dispensedescapes from the container during use until the liquid composition ispractically exhausted, i. c. has dropped to the level of the bottom ofthe inlet of tube 2. Since the transition of the propellant from liquidto gaseous phase is therefore not accompanied by any appreciable loss ofpropellant, the container, when nearly exhausted, usually contains amajor proportion of the original propellant in the gaseous form. Thisgas has a higher free energy content than that of the originalpropellant liquid, due to its absorption of at least a part of its heatof vaporization.

This emphasizes the desirability of keeping the quantity of propellantat a minimum consistent with effective delivery of the entire quantityof the liquid composition or product to be dispensed, since excessivequantities of propellant are very likely to lead to increased danger, inthe event of accidental breakage of the container, as more and more ofthe propellant becomes vaporized. This is an especially importantconsideration when glass containers are used, since the danger of flyingglass must be avoided. This danger is due not so much to any unprovokedrupture of the container, but to the forces released when the containeris accidentally dropped, or struck sharply enough to shatter it.

The propellant may be introduced into the container in any suitablemanner, for example by forcing it in through the valve 5 under highenough pressure to keep it in the liquid state, and after the liquidcomposition or product to be dispensed has been introduced, or bycooling it below its vaporization point and then putting it into thecontainer which also may have been cooled. Other ways of introducing areshown in the examples which follow.

The following examples will serve to show further the several featuresof the present invention, and are to be construed as illustrative ratherthan limiting.

Example I 400 ml. of an aqueous moth-proofing compound containing 0.6per cent sodium aluminum silicofluoride as active ingredient isintroduced into a pint glass bottle. A test tube containing 3.2 ml. ofthe cold liquefied propellant (CClF2)2, is placed in the bottle so thatno mixing occurs. The glass container is immediately closed with a capfitted with a discharge tube, valve, and nozzle. The container is theninverted in order to mix the two liquids. During spraying of themoth-proofing compound the container should be kept in a more or lessupright position so that the propellant will remain on the bottom. Thebottom inlet of the discharge tube or conduit (which is represented bynumeral 2 of the drawing) extends to between about one-eighth andone-sixteenth inch above the layer of liquid propellant at the bottom ofthe bottle. The quantity of propellant (1.23% by weight) is such that itwill give on vaporization at room temperature and pressure a volume ofabout 1 /2 times the volume of the pint bottle, this amount being morethan suflicient to expel all the contents. The initial pressure withinthe container is 13 p. s. i. g. at 70 F.

Example II grams of an aqueous deodorant is introduced into a four ouncephenolic resin lined tin coated aerosol can which is sealed with a capfitted with a valved discharge means connected to a tube. 5 grams of thepropellant, a mixture of about 70% CHaCCIFz and the balance CClzFz andCClaF, is added under pressure through the tube and a nozzle is thenfitted to the end of the tube. The quantity of propellant (5% by weight)is such that it will give a volume of gas when vaporized at roomtemperature and pressure of about ten times the volume of the can. Theinitial pressure within the container is 30 p. s. i. g. at 70 F.

It is preferable to exclude air from the container, so that the pressurewithin the container may be maintained when metal containers are used,so as to reduce the corrosion which is promoted by the presence of theoxygen of the air. Exclusion of air is accomplished when the containeris filled, for example by use of vacuum, or by flushing the containerwith an inert condensible gas such as Freon or steam, before or afterintroducing the propellant and the liquid to be sprayed.

What is claimed is:

1. A self-propelled liquid dispensing device comprising a gas-tightcontainer having relatively easily rupturable walls, a contained 3-phasefluid system comprising a liquid medium to be dispensed and a propellantpresent in both gaseous and liquid form and which in said liquid form issubstantially immiscible with and of greater specific gravity than saidliquid medium, said propellant having a boiling point not greater thanabout 20 C. and being present in an amount such that when entirely inthe gaseous state and calculated at C. and one atmosphere absolutepressure it will occupy a volume from about 1.2 to about times thevolume of the container, the gaseous phase of said propellant beingunder pressure, above said liquid medium, a conduit having a passageextending from a point within said container above, and near, the bottomof said liquid medium to a low pressure discharge orifice at a pointoutside of said container, and means for controlling the flow of fluidfrom within said container through said conduit passage to saiddischarge orifice.

2. A self-propelled liquid dispensing device in accordance with claim 1wherein the walls of said container are of glass.

3. A self-propelled liquid dispensing device in accordance with claim 1wherein the walls of said container are of thin metal.

4. A self-propelled liquid dispensing device as defined in claim 1 inwhich the propellant is a fluorinated hydrocarbon.

5. A self-propelled liquid dispensing device as defined in claim 1 inwhich the propellant is a fluorinated and chlorinated hydrocarbon havingfrom one to two carbon atoms per molecule.

6. A self-propelled liquid dispensing device as defined in claim 1 inwhich the propellant is a fluorinated hydrocarbon and in which theliquid medium to be dispensed contains a silicofluoride as an activeingredient.

7. A self-propelled liquid dispensing device comprising a gas-tightcontainer having relatively easily rupturable walls, a contained 3-phasefluid system comprising a liquid medium to be dispensed and a propellantpresent in both gaseous and liquid form and which in said liquid form issubstantially immiscible with and of greater specific gravity than saidliquid medium, said propellant having a boiling point not greater thanabout 20 C. and being present in an amount such that when entirely inthe gaseous state and calculated at 0 C. and one atmosphere absolutepressure it will occupy a volume from about 1.2 to about 5 times thevolume of the container, the gaseous phase of said propellant beingunder pressure, above said liquid medium, and means for conveying saidliquid medium from a point within the body thereof to a point outsidesaid container for ejection at said latter point, said propellant beingselected from the group consisting of fiuorinated, and chlorinated andfluorinated, low molecular weight saturated aliphatic hydrocarbonscontaining not more than two carbon atoms.

8. A self-propelled liquid dispensing device as defined in claim 7 inwhich the liquid medium is an aqueous medium.

9. A self-propelled liquid dispensing device as defined in claim 7 inwhich the liquid medium is an aqueous medium containing a silicofluorideand the propellant is a chlorinated and fluorinated hydrocarbon.

10. A self-propelled liquid dispensing device as defined in claim 7 inwhich the liquid medium is an aqueous medium containing sodium aluminumsilicofluoride, and

the propellant is tetrafluoro-dichloroethane in an amount of about 1.23%by weight of the composition.

11. A self-propelled liquid dispensing device comprising a gas-tightcontainer having relatively easily rupturable walls, a contained 3-phasefluid system comprising a liquid medium to be dispensed and a propellantpresent in both gaseous and liquid form and which in said liquid form issubstantially immiscible with and of greater specific gravity than saidliquid medium, said propellant having a boiling point not greater thanabout 20 C. and being present in an amount such that when entirely inthe gaseous state and calculated at 0 C. and one atmosphere absolutepressure it will occupy a volume of at least about 1.2 times the volumeof the container, the gaseous phase of said propellant being underpressure, above said liquid medium, and means for conveying said liquidmedium from a point within the body thereof to a point outside saidcontainer for ejection at said latter point, said propellant beingselected from the group con-' sisting of fluorinated, and chlorinatedand fluorinated, low molecular weight saturated aliphatic hydrocarbonscontaining not more than two carbon atoms.

12. A self-propelled liquid dispensing device comprising a gas-tightcontainer having relatively easily rupturable walls, a contained 3-phasefluid system comprising a major proportion of a liquid medium to bedispensed and a minor proportion of a propellant present in both gaseousand liquid form and which in said liquid form is substantiallyimmiscible with and of greater specific ,gravity than said liquidmedium, said propellant having a boiling point not greater than about 20C. and being present in an amount such that when entirely in the gaseousstate and calculated at 0 C. and one atmosphere absolute pressure itwill occupy a volume of at least about 1.2 times the volume of thecontainer, the gaseous phase of said propellant being under pressure,above said liquid medium, and means for conveying said liquid mediumfrom a point within the body thereof to a point outside said containerfor ejection at said latter point, said propellant being selected fromthe group consisting of fluorinated, and chlorinated and fluorinated,low molecular weight saturated aliphatic hydrocarbons containing notmore than two carbon atoms, the quantity and characteristics of saidpropellant being so adjusted as to be insufiicient to cause rupture ofthe container walls or dangerous propulsion of fragments in the event ofaccidental breakage.

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1. SELF-PROPELLED LIQUID DISPENSING DEVICE COMPRISING A GAS-TIGHTCONTAINER HAVING RELATIVELY EASILY RUPTURABLE WALLS, A CONTAINED 3-PHASEFLUID SYSTEM COMPRISING A LIQUID MEDIUM TO BE DISPENSED AND A PROPELLANTPRESENT IN BOTH GASEOUS AND LIQUID FORM AND WHICH IN SAID LIQUID FORM ISSUBSTANTIALLY IMMISCIBLE WITH AND OF GREATER SPECIFIC GRAVITY THAN SAIDLIQUID MEDIUM, SAID PROPELLANT HAVING A BOILING POINT NOT GREATER THANABOUT 20* C. AND BEING PRESENT IN AN AMOUNT SUCH TAHT WHEN ENTIRELY INTHE GASEOUS STATE AND CALCULATED AT 0* C. AND ONE ATMOSPHERE ABSOLUTEPRESSURE IT WILL OCCUPY A VOLUME FROM ABOUT 1.2 TO ABOUT 5 TIMES THEVOLUME OF THE CONTAINER, THE GASEOUS PHASE OF SAID PROPELLANT BEINGUNDER PRESSURE, ABOVE SAID LIQUID MEDIUM, A CONDUIT HAVING A PASSAGEEXTENDING FROM A POINT WITHIN SAID CONTAINER ABOVE, AND NEAR, THE BOTTOMOF SAID LIQUID MEDIUM TO A LOW PRESSURE DISCHARGE ORIFICE AT A POINTOUTSIDE OF SAID CONTAINER, AND MEANS FOR CONTROLLING THE FLOW OF FLUIDFROM WITHIN SAID CONTAINER THROUGH SAID CONDUIT PASSAGE TO SAIDDISCHARGE ORIFICE.